Monday, March 20, 2017



The urinary system, or excretory system, removes waste from the blood in the form of urine. This system also keeps a stable balance of salts and other substances in the blood, and produces erythropoietin, a hormone that aids the formation of red blood cells.

The urinary system is made up of:
- Kidneys: two bean-shaped organs that filter waste from the blood and produce urine
- Ureters: two tubes that take urine from the kidney to the bladder
- Bladder: a sac that hold urine until it leaves the body
- Sphincter Muscles: help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder
- Nerves in the Bladder: alert a person when it is time to urinate
- Urethra: the tube that carries urine from the bladder out of the body
- Nephrons: removes excess water, wastes, and other substances from your blood, and returns substances like sodium, potassium or phosphorus whenever any of these substances run low in your body

The urinary system works closely with the circulatory and endocrine systems. Blood that circulates through the body passes through one of the two kidneys. Urea, uric acid, and water are removed from the blood and most of the water is transported back into the system. The endocrine system is the major controller of the urinary system. "As levels of compounds and fluids are monitored, kidney function must be constantly altered to provide the best internal environment for your cells. If you drink too much water, hormones are released that allow for more urine production. If you are dehydrated, less urine will be produced. The kidneys are also tied to the endocrine system with the adrenal gland position on the top of each kidney. The adrenals release adrenaline into your body" (

The urinary system is like a coffee machine. The on/off switch activates the coffee machine like how the nerves in the bladder alert a person when it is time to urinate. The carafe stores the coffee until someone wants to drink it, similar to how the bladder stores urine until it is ready to leave the body, and the water filtration is like the kidneys.


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